KIEV, Ukraine — Lawmakers in Ukraine accepted the resignation of the defense minister Tuesday as thousands of troops began withdrawing from the Crimean Peninsula, now controlled by Russia.

In an address to parliament, Igor Tenyukh said he rejected criticism that he had failed to issue clear instructions to troops, but that he reserved the right to step down. Lawmakers initially refused his resignation, but later accepted it. A majority then voted to appoint Col. Gen. Mikhail Kovalyov as his replacement.

Authorities in Ukraine have come under criticism for their often-hesitant reaction to Russia's annexation of Crimea, which was formalized following a hastily organized referendum this month.

In Crimea, Ukrainian soldiers piled onto buses and began their journey to Ukrainian territory on Tuesday, as former comrades saluted them from outside a base overrun by Russian forces.

Tenyukh said he had received requests to leave Crimea from about 6,500 soldiers and family members, meaning about two-thirds of the 18,800 military personnel and relatives stationed there were so far taking their chances in the peninsula newly absorbed by Russia.